The present invention relates to apparatus and methods for heat setting of yarn, especially carpet yarn.
The present invention also relates to apparatus and methods for converting existing yarn heat-setting machines to be adjustably operable for processing a wide range of yarn crimp characteristics from essentially straight-set yarn to highly crimped yarn.
A presently available commercial machine for achieving a relatively straight-set yarn, with low crimp, is the Suessen GVA for Carpet Yarn Heat-Setting, described in the technical sales bulletin 017.1735E, published by the American Suessen Corporation of Charlotte, N.C. (the Suessen Straight-Set Yarn Machine). See also U.S. Pat. Nos. 4,316,370; 4,507,832; and 4,513,514 for descriptions of machines for heat-setting carpet yarn that yield a relatively straight-set yarn.
The Suessen Straight-Set Yarn Machine accommodates continuous heat treatment processing of yarn by conveying the yarn through a heat treatment chamber which is at atmospheric pressure and is open to the atmosphere at both its inlet and outlet ends. In this system, the yarns are wrapped around travelling endless transport ropes in a relaxed skein form with basically no crimp or twist in the yarn so that when it is heat treated it ends up with a straight-set yarn configuration. Since straight-set carpet yarn has enjoyed a substantial portion of the market for carpet yarn for the last several years, this Suessen Straight-Set Yarn Machine has been commercially successful as it produces such straight-set yarn in an economical and reliable repetitive manner.
However, there is also a substantial commercial demand for so called textured or high crimp carpet yarn and various systems have been developed for processing this type of yarn. One such system is the Suessen/Horauf GVA for Texturing and Heat-Setting Carpet Yarns, described in the published Suessen/Horauf technical sales brochure entitled "GVA for Texturing and Heat-Setting Carpet Yarns" (hereinafter "The Suessen Textured Yarn Machine"). See also U.S. Pat. Nos. 3,298,079 and 4,169,707 for disclosures of systems for producing textured or high crimp carpet yarns.
The Suessen Textured Yarn Machine processes the yarn through a so-called "stuffer box", disposed upstream of an open weave conveyor belt which carries the yarn through a heat-setting chamber. At the outlet end of the stuffer box, the yarn is piddled in a spaghetti-like pattern onto the flat conveyor belt. The conveyor belt carries the yarn through the heat-setting chamber in the spaghetti-like pattern so that it is heat set with relatively high crimp. This Suessen Textured Yarn Machine has proven to be an economical and reliable system for producing textured carpet yarn.
Although the Suessen Straight-Set Yarn Machine and the Suessen Textured Yarn Machine are quite economical and reliable for producing the respective straight-set yarn and textured yarn, neither of these machines is adaptable for producing both straight-set and textured yarn. Since carpet yarn producers which use these .heat treating machines would like to supply their customers with both straight-set carpet yarn and textured carpet yarn, with the ratio depending on ever-changing market conditions, there is a demand for machines producing both types of yarn. One solution is to use components of both the Suessen Straight-Set Yarn Machine and the Suessen Textured Yarn Machine and to modify the machines so as to switch between straight-set yarn production and textured yarn production. Both of these systems utilize the same heat-setting chamber and yarn draw-off systems. The Suessen Straight-Set Yarn Machine can be modified to a configuration corresponding to the Suessen Textured Yarn Machine by removing the conveying system for the straight-set yarn and substituting the stuffer box and belt system of the Suessen Textured Yarn Machine. However, the modification to change from straight-set yarn production to textured yarn production requires two to three work days, with consequent labor costs in making the modification. Also lost production during the modification is very costly as these machines are intended to operate continuously, 24 hours a day, seven days a week, to optimize their production efficiency.
An object of the present invention is to overcome the problems in the prior art by providing new methods and apparatus which facilitate the use of a single machine to produce both straight-set yarn and highly crimped yarn by simply adjusting the machine with substantially no loss in production time and no machine modification costs.
Another object of the present invention is to provide new methods and apparatus for converting existing machines, such as the Suessen Textured Yarn Machine so that they can be used to process both straight-set yarn and highly crimped textured yarn, with transition between yarn types requiring virtually no down time.
Another object of the present invention is to provide new methods and apparatus which facilitate production of new types of yarn intermediate the presently known straight-set yarn and highly crimped textured yarn, thereby expanding the range of textured carpet yarn which the carpet yarn suppliers can produce, with consequent expanded options for carpet designers to enhance the variations in carpet textures ultimately produced. In this connection, the relatively straight-set yarn is used for producing commercial straight plush yarns for relatively short pile carpets, while the highly crimped textured yarn is used for producing deeper pile, plusher and shag-type carpets.
Another object of the present invention is to provide new methods and apparatus which permit use of yarn with less initial twist (for example "balanced" twist yarn) to be processed and crimped, as compared to the more highly twisted yarn required by present machines for producing textured carpet yarn. Since this low twist "balanced" yarn is less expensive than more highly twisted yarn, the present invention therefore permits a more economical production of textured carpet yarn.
The above objects are achieved according to preferred embodiments of the invention by providing a new yarn laying system for laying yarn on a conveyor belt which continuously supplies yarn to a heat-setting chamber. This new yarn laying system lays the yarn in predetermined patterns on the moving conveyor belt and is adjustable in a simple manner to vary the yarn pattern laying on the belt and thereby change the degree of crimp achieved in the heat-setting chamber.
In certain preferred embodiments of the invention, a yarn laying system is provided which utilizes a bent yarn supply tube which is driven by an adjustable speed driving motor so that its yarn outlet end oscillates transversely of a longitudinal moving conveyor belt to thereby control the pattern of yarn laying on the conveyor belt.
In certain preferred embodiments of the invention, pressurized air is supplied to the yarn supply tube to aid in transport of the yarn through the yarn supply tube. An adjustable yarn deflecting plate is also provided in certain preferred embodiments of the invention for deflecting the yarn as it falls from the yarn supply tube to the conveyor belt under certain yarn laying pattern conditions.
According to especially advantageous preferred embodiments of the invention, an electronic control system is provided for controlling (i) the speed of yarn feed rollers which control the speed of yarn supplied to the yarn supply tube; (ii) the speed of the driving motor which controls the oscillating speed of the yarn supply tube; and (iii) the speed of the conveyor belt. Also, in preferred embodiments, the vertical distance between the conveyor belt surface and the outlet end of the yarn supply tube is adjustable.
Certain preferred embodiments of the invention include a conversion or replacement kit including a detachable yarn laying system which can be readily substituted for the stuffer box and traverse assembly of the Suessen Textured Yarn Machine. This detachable yarn laying system includes the above-noted yarn supply tube and drive therefor.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.